JP2024054029A - Front body structure - Google Patents

Abstract

To prevent deformations of a cabin and a battery pack by absorbing collision energy by a vehicle body front structure in multiple frontal collision forms.SOLUTION: A vehicle body front structure includes: front side frames 100 located on both sides in a vehicle width direction of a front part of a vehicle V; a cross member 110A; a bumper beam 120; triangular reinforcements 200 each including a bottom surface portion BT coupled to the bumper beam 120 and a tip portion 200b protruding toward an inner side of a rear part of the vehicle; and fixing brackets 200a each fixing the reinforcement 200 to the front side frame 100. An axial direction SS of each reinforcement intersects with an outer surface as seen in the vehicle width direction of the front side frame 100 on the vehicle front side relative to a coupled portion CN between the front side frame 100 and the cross member 110A.SELECTED DRAWING: Figure 3

Description

The present invention relates to a vehicle front structure.

In general, in a frontal collision of a vehicle, preventing deformation of the cabin, which is the space in which passengers sit, is an effective way to reduce injuries to occupants, and various methods have been developed to achieve this. One of these methods that has become widespread in recent years is a structure that absorbs collision energy with a structure in front of the cabin.

On the other hand, when the vehicle is a hybrid vehicle, an electric vehicle, or the like, a battery pack serving as a power source for the vehicle may be mounted on the floor below the cabin.
The battery pack stores power to drive the vehicle, and if the battery pack is deformed or broken due to a frontal collision of the vehicle or the like, there is a risk of a sudden abnormal reaction.
Therefore, in the case of hybrid vehicles, electric vehicles, and the like, it is becoming increasingly important to have a structure that does not deform the cabin so as to prevent damage to the battery pack.

In addition, in the case of a frontal collision of a vehicle, it is necessary to consider several collision types, such as a full-overlap collision in which the entire front surface of the vehicle collides with a colliding body, an offset collision in which one side of the front surface of the vehicle collides with a colliding body, or a small overlap collision with an offset rate of about 25%.
For this reason, there is a demand for a structure that prevents the cabin and battery pack from deforming by absorbing the collision energy using a structure in front of the cabin or battery pack in each collision type.

In response to the above-mentioned requirements, a structure has been proposed that includes a bumper reinforcement (bumper beam) that extends in the vehicle width direction in front of the vehicle, a pair of left and right side rails (front side frames) that extend along the vehicle front-rear direction on the outer sides of the vehicle width direction, and a brace (reinforcement) that is connected to the bumper beam on the outer side of the vehicle than the front side frames. In the event of collision energy due to a small overlap collision, the reinforcement engages with a load-receiving portion provided on the front side frame and transmits the load via the cross member to the front side frame on the opposite side in the vehicle width direction (see, for example, Patent Document 1).

JP 2017-047780 A

However, in the technology of Patent Document 1, the reinforcement is configured to transmit the collision energy generated by a small overlap collision to the front side frame and cross member by pressing a load receiving portion provided on the front side frame, and the transmission direction is limited to the rear or rear-to-side direction. Therefore, there is a problem that the collision energy may not be efficiently dispersed and transmitted.

Therefore, the present invention has been made in consideration of the above-mentioned problems, and provides a vehicle front body structure that can prevent deformation of the cabin and battery pack even in multiple frontal collision types.

Form 1: One or more embodiments of the present invention propose a vehicle body front structure including a pair of front side frames extending in the vehicle longitudinal direction on both sides of the front of the vehicle in the vehicle width direction, a cross member extending in the vehicle width direction at the front side of the vehicle and connecting to the front side frames, and a bumper beam connected to the vehicle front end of the front side frame, extending in the vehicle width direction, and having curved portions at both ends facing the vehicle rear side, the vehicle body front structure includes a triangular reinforcement whose bottom surface is connected to the bumper beam and whose tip end protrudes toward the inside of the rear of the vehicle, and a fixing bracket that fixes the reinforcement to the front side frame, the tip end of the reinforcement has a D-shape with an R-shape extending in the vehicle up-down direction, and the axial direction of the reinforcement fixed to the front side frame intersects with the vehicle width direction outer surface of the front side frame on the vehicle front side of the connecting portion between the front side frame and the cross member.

Mode 2: One or more embodiments of the present invention propose a vehicle body front structure in which a reinforcing member having a recess is installed on the front side frame from the vehicle rear part of the joint with the cross member to the inside of the joint, from the vehicle width direction front outer surface to the vehicle width direction rear inner surface of the front side frame.

According to one or more embodiments of the present invention, deformation of the cabin and battery pack can be prevented even in multiple frontal collision types.

1 is a schematic diagram of a vehicle according to an embodiment of the present invention, viewed from above. 2 is a schematic view of the vehicle body front structure shown in FIG. 1 as viewed from above. 3 is a perspective view of the TS unit shown in FIG. 2 from above with a motor unit and a front wheel removed. FIG. 1A and 1B are plan views showing deformation of a vehicle front structure during a full-wrap collision in a vehicle front structure according to an embodiment of the present invention, as viewed from above, in which (a) is a plan view before the collision, and (b) and (c) are plan views showing deformation during a frontal collision in chronological order. 1A and 1B are plan views showing deformation of a vehicle front structure during a small wrap collision in an embodiment of the vehicle front structure of the present invention, viewed from above, where (a) is a plan view before the collision, and (b) and (c) are plan views showing deformation during a frontal collision in chronological order.

Below, a vehicle V to which the vehicle body front structure S according to this embodiment is applied will be described with reference to Figures 1 to 5. Note that the arrow FR, as appropriate shown in the drawings, indicates the front (front) of the vehicle V shown in Figure 1, the arrow UP indicates the upward direction as seen from the front, and the arrow LH indicates the leftward direction as seen from the front. In addition, in the following description, when the up/down, front/rear, and left/right directions are used, they refer to the up/down direction as seen from the front, the front/rear direction as seen from the front, and the left/right direction as seen from the front, unless otherwise specified.

<Embodiment>
The configuration of a vehicle body front structure S according to this embodiment, which is provided on a vehicle V, will be described with reference to FIGS.

<Configuration of Vehicle V>
The vehicle V is, for example, an electric vehicle using the power unit section 20 as a driving source. Note that the vehicle V may be, for example, a hybrid electric vehicle having a plurality of driving sources, such as an engine and the power unit section 20.

As shown in FIG. 1, the vehicle V includes a front wheel 10, a power unit 20, a battery pack 30, a toe board 40, a torque box 50, a side sill 60, and a front vehicle structure S (the shaded area surrounded by a dashed line in FIG. 1) inside the vehicle body VS.

The power unit 20 is a drive device that is made up of a motor, a transmission, a clutch, a drive shaft, etc. (not shown) that drives the front wheels 10. The power unit 20 is installed in a space surrounded by the front side frame 100 and cross members 110A and 110B (described later), and is fixed in a state in which it is placed on the upper surface side of the front side frame 100.

The battery pack 30 is formed, for example, in the shape of a flattened box. Inside the battery pack 30, many battery cells are connected in series, and it is possible to output high voltage to be supplied to the power unit section 20, and to store the power required for the vehicle to run. The battery pack 30 is installed in a space surrounded by sturdy frames such as the torque box 50 and side sills 60 described below. The battery pack 30 is used, for example, in vehicles such as electric vehicles (EVs) and hybrid electric vehicles (HEVs).

The toe board 40 is a partition wall that is raised in the vertical direction of the vehicle on the front side of the cabin CA and separates the front wheel drive system of the vehicle V from the cabin CA. The toe board 40 is joined by welding or the like to the upper rear side of the front side frame 100, which will be described later.

The torque box 50 is a member that is interposed between a front side frame 100 and a side sill 60, which will be described later, and connects the front side frame 100 and the side sill 60. The torque box 50 is a framework that extends in the vehicle width direction on the bottom surface of the vehicle V, and is joined to one end of each of the left and right front side frames 100 by welding or the like. The torque box 50 is formed from a metal having high rigidity or the like, and has a substantially rectangular closed cross-sectional shape. The torque box 50 is located in front of the battery pack 30, and one end of the torque box 50 is joined to one end of each of the left and right side sills 60 by welding or the like.
Further, left and right front side frames 100, which will be described later, are joined at one end to the front and top sides of the torque box 50 by welding or the like.
The area behind the torque box 50 is a protection area PA, which is an area that prevents deformation of the cabin CA located above the protection area PA and the battery pack 30 located below the protection area PA.

The side sills 60 are provided on the bottom surface of the vehicle on both sides in the vehicle width direction. The side sills 60 are frameworks extending in the front-to-rear direction, are made of highly rigid metal or the like, and have a substantially rectangular closed cross-sectional shape. The side sills 60 form the bottom sides of both sides of the protection area PA.

The vehicle front structure S is configured inside the vehicle front compartment FA, forward of the torque box 50. The configuration of the vehicle front structure S will be described later.

<Configuration of vehicle body front structure S>
The vehicle body front structure S according to this embodiment will be described with reference to Figs.
The vehicle body front structure S is configured symmetrically in the vehicle width direction.
As shown in FIG. 2, the vehicle front structure S includes a front side frame 100 (front side frames 100A, 100B), a cross member 110 (cross members 110A, 110B), a bumper beam 120, and a reinforcement 200 (reinforcements 200A, 200B).

(Regarding the front side frame 100)
The front side frames 100 are provided in a pair on both sides in the vehicle width direction, are located on the side surfaces of the power unit section 20 that drives the front wheels of the vehicle V, and extend in the front-to-rear direction of the vehicle. The front side frames 100 form the skeleton of the vehicle V, and are formed from a highly rigid metal or the like, with a substantially rectangular closed cross-sectional shape. The front end of the front side frame 100 is joined to the bumper beam 120 by welding or the like, and the rear end of the front side frame 100 is joined to the torque box 50 by welding or the like.
3, the front side frame 100 is provided with a reinforcing member HC (reinforcing members HCA, HCB) from the vehicle rear portion of the joint portion CN (joint portions CNA, CNB) between the front side frame 100 and the cross member 110A to the inside of the joint portion. The reinforcing member HC is made of metal or hard resin, etc., and is provided inside the front side frame 100. The reinforcing member HC has a recess HS (recess HSA, HSB) from the vehicle width direction front outer surface to the vehicle width direction rear inner surface of the front side frame 100. Specifically, the reinforcing member HC has an arc-shaped recess HS that connects a line where the vehicle front side surface of the cross member 110A and the vehicle outer side surface of the front side frame 100 intersect, and a line where the vehicle rear side surface of the cross member 110A and the vehicle rear inner side of the front side frame 100 intersect.

(Regarding the cross member 110)
As shown in Fig. 2, the cross members 110A, 110B extend between the front side frames 100 on both sides in the vehicle width direction. The cross member 110A is provided on the vehicle front side of the front side frame 100, and the cross member 110B is provided on the vehicle rear side of the front side frame 100. The cross members 110A, 110B are formed from metal or the like and have a substantially rectangular closed cross-sectional shape. The ends of the cross members 110A, 110B are joined to the front side frames 100 on both sides in the vehicle width direction by welding or the like.

(Regarding the bumper beam 120)
The bumper beam 120 extends in the vehicle width direction at the front end of the vehicle and constitutes a framework in the front part of the vehicle. The bumper beam 120 is formed of metal or the like and has a substantially rectangular closed cross-sectional shape. The bumper beam 120 is joined to the vehicle front end of the front side frame 100 on both sides in the vehicle width direction by welding or the like, and the outer side in the vehicle width direction of the joint with the front side frame 100 is bent toward the rear side of the vehicle. In addition, the center of the bumper beam 120 is curved so that the center part in the vehicle width direction is convex toward the front side of the vehicle in a plan view.

In addition, the front body structure S is formed with a strong, lattice-shaped framework by combining front side frames 100 on both sides in the vehicle width direction, cross members 110A and 110B provided in front of and behind the power unit section 20, a bumper beam 120, a torque box 50, and a side sill 60.

(About Reinforce 200)
As shown in FIG. 3, the reinforcement 200 has a bottom surface BT (bottom surface BTA, BTB) joined to the bumper beam 120 by welding or the like, and a tip portion 200b (tip portions 200bA, 200bB) protruding toward the inside of the rear of the vehicle, forming a substantially triangular shape. The reinforcement 200 is formed of metal or the like, and has a substantially triangular closed cross section formed by one side of the bottom surface BT on the vehicle front side in a plan view and two sides longer than the side of the bottom surface BT facing the inside of the rear of the vehicle. The tip portion 200b extends toward the joint portion CN. The tip portion 200b has a D-shape with an R-shape extending in the vehicle up-down direction.
In addition, on the vehicle rear inner surface of the reinforcement 200, a fixed bracket 200a (fixed bracket 200aA, 200aB) for fixing the reinforcement 200 to the front side frame 100 is disposed integrally with the reinforcement 200 by welding or the like. The fixed bracket 200a is formed in a substantially rectangular flat plate shape from a steel plate or the like. The fixed bracket 200a is folded back toward the vehicle front side at the tip 200b. In addition, the fixed bracket 200a is provided with a long hole HL that penetrates in the plate thickness direction with the vehicle front-rear direction as the longitudinal direction. The reinforcement 200 is fixed to the front side frame 100 by fixing the long hole HL of the fixed bracket 200a to the front side frame 100 by a bolt or the like. A gap is provided between the tip 200b and the front side frame 100. In addition, the axial direction SS (axial directions SSA, SSB) of the reinforcement 200 fixed to the front side frame 100 facing toward the inside of the rear of the vehicle intersects with the vehicle width direction outer surface of the front side frame 100 on the vehicle forward side of the reinforcing member HC.

<Action and Effects>
The vehicle body front structure S of this embodiment, configured as described above, prevents deformation of the cabin CA and battery pack 30 provided in the protective area PA by absorbing the collision energy in the vehicle body front structure S when an impact object collides head-on with the vehicle V.
In the case of a full-overlap collision, the impact absorbing structures on both sides of the vehicle width direction act, while in the case of an overlap collision or small overlap collision, the impact absorbing structure on the side where the collision occurred acts mainly. Below, the action in the case of a full-overlap collision will be described with reference to Figures 4(a) to 4(c).

(In the case of a full-wrap collision)
When a colliding object FB collides head-on with a vehicle V, collision energy is generated from the direction indicated by an arrow A. In the case of a full-wrap collision, as shown in FIG. 4A, a colliding object FB collides head-on with a vehicle V, and collision energy is generated from the direction indicated by an arrow A.

4B, collision energy from the front side indicated by arrow A is transmitted to the front side frame 100 and the reinforcement 200 via the bumper beam 120. Collision energy indicated by arrow B (arrows BL, BR) is transmitted to the front side frame 100 from the front side of the vehicle toward the rear side. Then, the front end of the front side frame 100 is crushed by the collision energy, and the collision energy is absorbed by the deformation of the front end of the front side frame 100.
As the crushing of the front side frame 100 progresses, the collision energy in the direction of the arrow C (arrows CL, CR) is transmitted to the reinforcement 200. At this time, the collision energy in the direction of the arrow B and the collision energy in the direction of the arrow C transmits the collision energy toward the rear of the vehicle to the fixing bracket 200a of the reinforcement 200. Then, the reinforcement 200 and the fixing bracket 200a are pushed in the direction shown by the arrow D (arrows DL, DR). Since the tip portion 200b of the reinforcement 200 has a D-shaped tip shape, the vehicle width direction outer surface of the front side frame 100 is smoothly pushed in the direction of the arrow D. Then, the fixing bracket 200a is released from the front side frame 100 by the elongated hole HL fixed by a bolt or the like sliding toward the rear of the vehicle and breaking, and the reinforcement 200 loses the fixed axis and does not interfere with the absorption of the collision energy.

When the collision energy becomes larger, as shown in FIG. 4C, the crush of the front side frame 100 advances to the position of the cross member 110A on the vehicle front side, and the collision energy is absorbed by the deformation of the front side frame 100. The collision energy indicated by the arrows B and E (arrows EL, ER) transmitted to the front side frame 100 is transmitted to the cross members 110A and 110B provided in front and behind the power unit section 20 and to the torque box 50. The collision energy in the direction indicated by the arrows G (arrows GL, GR) is transmitted to the cross member 110B provided on the vehicle rear side of the power unit section 20, and the cross member 110B is crushed. The collision energy indicated by the arrows F (arrows FL, FR) transmitted to the torque box 50 is dispersed to the side sill 60.
As described above, the reinforcement 200 and the fixed bracket 200a lose the fixed axis and do not interfere with the absorption of the collision energy. The collision energy is dispersed to the lattice-shaped strong skeleton formed by combining the front side frames 100 and 100B on both sides in the vehicle width direction, the cross members 110A and 110B provided in front of and behind the power unit section 20, the bumper beam 120, the torque box 50, and the side sill 60, and is absorbed by the deformation of the lattice-shaped skeleton.

When the input of collision energy ends and the transmission of collision energy to the front side frame 100 ends, the absorption of collision energy through deformation of the vehicle front structure S ends.

(In case of small wrap collision)
On the other hand, in the case of a small lap collision, as shown in Fig. 5(a), the colliding object FB collides with either the left or right side of the vehicle V, and collision energy is generated from the direction indicated by the arrow SA. Figs. 5(a) to 5(c) explain a case where the collision occurs on the left side of the vehicle V as viewed from the front.

As shown in FIG. 5(b), the collision energy from the front, indicated by arrow SA, is transmitted to the front side frame 100 and the reinforcement 200 from the directions indicated by arrows SB and SC via the bumper beam 120. The collision energy indicated by arrow SB is transmitted to the front side frame 100 toward the rear of the vehicle. The front side of the front side frame 100 is crushed by the collision energy, and the collision energy is absorbed by the deformation of the front side of the front side frame 100.

The reinforcement 200 receives collision energy in the direction of the arrow SC from the bumper beam 120. The reinforcement 200 receives collision energy indicated by the arrow SD. The direction indicated by the arrow SD is substantially the same as the axial direction SS of the reinforcement 200 facing the inside of the rear of the vehicle, so collision energy that deforms the front side frame 100 is transmitted to the tip 200b of the reinforcement 200. Since the axial direction SS of the reinforcement 200 faces the vehicle front side further than the reinforcing member HC, the tip 200b of the reinforcement 200 rides on the recess HS of the reinforcing member HC provided inside the front side frame 100 while deforming the front side frame 100. The reinforcement 200 is guided by the recess HS toward the inside of the rear of the vehicle while crushing the front side frame 100.

When the collision energy becomes even larger, as shown in FIG. 5C, on the side where the collision occurred, the crushing of the front side frame 100 advances to the position of the cross member 110A provided in front of the power unit section 20. The collision energy is further transmitted to the reinforcement 200 from the direction indicated by the arrow SC, and the reinforcement 200 is fixed to the cross member 110A by submerging while deforming the cross member 110A. The collision energy indicated by the arrow SD is transmitted to the cross member 110A, and the cross member 110A is crushed and deformed. Also, on the side opposite to the side where the collision occurred, the collision energy indicated by the arrow SJ transmitted via the cross member 110A deforms the front side frame 100B on the side opposite to the side where the collision occurred.
In addition, the collision energy indicated by arrow SG that is transmitted to the front side frame 100 toward the rear of the vehicle is dispersed in the direction toward the cross member 110B indicated by arrow SI and in the direction toward the torque box 50 indicated by arrow SH.
As described above, the collision energy transmitted through reinforcement 200 is dispersed throughout the strong, criss-cross shaped skeleton formed by combining front side frames 100 and 100B on both sides in the vehicle width direction, cross members 110A and 110B provided in front of and behind power unit section 20, bumper beam 120, torque box 50, and side sill 60, and is absorbed by deformation of the criss-cross shaped skeleton.

When the input of collision energy ends and the transmission of collision energy to the front side frame 100 ends, the absorption of collision energy through deformation of the vehicle front structure S ends.

As described above, the vehicle body front structure S according to this embodiment is a vehicle body front structure including a pair of front side frames 100 (the opposite side in the vehicle width direction is front side frame 100B) extending in the vehicle fore-and-aft direction on both sides of the front of the vehicle V in the vehicle width direction, cross members 110A and 110B extending in the vehicle width direction at the front of the vehicle to connect front side frame 100 and front side frame 100B, and a bumper beam connecting the vehicle front end of front side frame 100 and the vehicle front end of front side frame 100B, extending in the vehicle width direction, and having bent portions at both ends facing the vehicle rear side. The reinforcement 200 has a triangular shape with a bottom portion BT connected to the bumper beam 120 and a tip portion 200b protruding toward the inside of the rear of the vehicle, and a fixing bracket 200a that fixes the reinforcement 200 to the front side frame 100, and the tip portion 200b of the reinforcement 200 has a D-shape with an R-shape extending in the vertical direction of the vehicle, and the axial direction SS of the reinforcement 200 fixed to the front side frame 100 intersects with the outer surface of the front side frame 100 in the vehicle width direction, further forward of the joint CN between the front side frame 100 and the cross member 110A.
In the case of a full-lap collision, the reinforce 200 is transmitted with collision energy toward the rear of the vehicle. Since the tip 200b of the reinforce 200 has a D-shaped tip, the outer side of the front side frame 100 is smoothly pushed toward the rear of the vehicle. Then, the fixing bracket 200a comes off the front side frame 100, and the tip 200b of the reinforce 200 is guided to a position that does not interfere with the absorption of impact energy by the framework having a lattice shape by losing the fixed axis. On the other hand, in the case of a small-lap collision, the reinforce 200 is transmitted with collision energy toward the axial direction SS of the reinforce 200. The reinforce 200 is fixed by slipping into the cross member 110A while deforming the front side frame 100.
That is, in the case of a full-lap collision, the vehicle body front structure S moves the reinforcement 200 to a position that does not interfere with the absorption of impact energy by the framework having a lattice shape, and in the case of a small-lap collision, the reinforcement 200 is fixed to the cross member 110A, thereby dispersing the collision energy to the member that is optimal for the collision type. Therefore, the vehicle body front structure S can disperse and absorb the collision energy to the member that is optimal for the collision type inside the vehicle front room FA.
Therefore, deformation of the cabin CA and the battery pack 30 present in the protection area PA can be prevented.

In addition, in the front body structure S of this embodiment, a reinforcing member HC having a recess HS extending from the front outer surface of the front side frame 100 in the vehicle width direction to the rear inner surface in the vehicle width direction is installed in the front side frame 100 inside the joint CN between the front side frame 100 and the cross member 110A.
In the case of a small lap collision, since the axial direction SS of the reinforcement 200 faces further toward the front of the vehicle than the reinforcing member HC, the tip portion 200b of the reinforcement 200 rides up on the recessed portion HS of the reinforcing member HC provided inside the front side frame 100. The reinforcing member HC guides the reinforcement 200 to the cross member 110A by the recessed portion HS, and fixes the reinforcement 200 to the cross member 110A.
In other words, the reinforcing member HC guides the reinforcement 200 to the cross member 110A by the recess HS, and reliably fixes the reinforcement 200 to the cross member 110A, so that the vehicle body front structure S can disperse the collision energy to the front side frame 100B on the opposite side to the side where the collision occurred. Therefore, the vehicle body front structure S can disperse and absorb the collision energy to the member that is optimal for the collision type inside the vehicle front room FA.
Therefore, deformation of the cabin CA and the battery pack 30 present in the protection area PA can be prevented.

The above describes an embodiment of the present invention in detail with reference to the drawings, but the specific configuration is not limited to this embodiment and includes designs that do not deviate from the gist of the present invention.

REFERENCE SIGNS LIST 1; vehicle 10; front wheel 20; power unit 30; battery pack 40; toe board 50; torque box 60; side sill 100; front side frame 110A; cross member 110B; cross member 120; bumper beam 200; reinforcement 200a; fixing bracket 200b; tip portion CA; cabin (passenger compartment)
FA: Vehicle front compartment HC: Reinforcement member HS: Recess PA: Protective area S: Vehicle front structure SA: Impact absorbing structure

Claims (2)

A vehicle body front structure including a pair of front side frames extending in a vehicle longitudinal direction on both sides of a front portion of a vehicle in a vehicle width direction, a cross member extending in the vehicle width direction at a front side of the vehicle and connected to the front side frames, and a bumper beam connected to a front end of the front side frames, extending in the vehicle width direction, and having bent portions at both ends facing toward the rear side of the vehicle,
A triangular reinforcement having a bottom portion connected to the bumper beam and a tip portion protruding toward the inside of the rear portion of the vehicle;
A fixing bracket that fixes the reinforcement to the front side frame;
Equipped with
The tip portion of the reinforcement has a D-shape with an R-shape extending in the vehicle up-down direction,
a front body structure characterized in that the axial direction of the reinforcement fixed to the front side frame intersects with the vehicle width direction outer surface of the front side frame, further forward of the vehicle than the joint between the front side frame and the cross member. 2. The front body structure according to claim 1, wherein a reinforcing member having a recess is installed on the front side frame from the vehicle rear portion of the joint with the cross member to the inside of the joint, the recess being located from the vehicle width direction front outer surface of the front side frame to the vehicle width direction rear inner surface of the front side frame.